BTN8982TA easy to burn...

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User20677
Level 1
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First question asked First reply posted
I have a problem with BTN8982TA H-Bridge - when I change the direction of of the motor until it stops his movement - I have two IC's burned.

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I just put 24V power supply, and PWM is constant 0, INA & INB pulled up. I Start the motor by giving 1 on PWM and 0 on (for example) INA. When I put 1 on INA and 0 pn PWM the motor is freewheeling.
If I don't wait until the motor stops his movement and I put 1 on INB (opposite direction) and 1 on PWM - both drivers are burned.

I checked - if I have 2Ohm resistore instead of motor the problem doesn't exist.
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JingN
Moderator
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Moderator
First like received First solution authored 25 replies posted
Please check the voltage at VS pin. Changing the motor direction without a proper braking could cause a high voltage at VS pin. If the motor is still working as a generator, the voltage might exceed the max. rating as shown in the figure below:
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User20677
Level 1
Level 1
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I checked your suggestion - the voltage on Vs not exceed 30V when the driver is burned.

I also try to reduce the voltage to 14.7V just for test, and it burned also in the same way 😞 - the Vs not exceed 20V when it burned
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JingN
Moderator
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First like received First solution authored 25 replies posted
Maybe you can check the output voltage to see if you have undervoltage toggling there. If yes, the overtemperature protection could react too late to protect the device.
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User20677
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Level 1
First question asked First reply posted
You mean when the output voltage is lower than GND due to inductance?
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JingN
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First like received First solution authored 25 replies posted
Yes, the one we described in chapter 3.2.2 in our application note. It causes power dissipation and might destroy the device.
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User20677
Level 1
Level 1
First question asked First reply posted
I checked that the voltage drop when the motor starts, but I didn't see the effect described in chapter 3.2.2.

I burned a lot of devices trying to investigate the problem - it occur before I change the direction.

I analysis that the problem occurs when I turn the motor off (INH floating, IN pulled down) and Low Side mosfet in the driver sometimes has burned out. So when I change direction it cause damage of full bridge due to shortcircuit.

Always low side mosfet are burned first.
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JingN
Moderator
Moderator
Moderator
First like received First solution authored 25 replies posted
Could you please share the input pattern you use? Example: IN = 1, INH = 1; --> IN = 0, INH = 0 --> ...
Maybe also some screen shot from waveform, so we can help you more in details.
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